Abstract:

Abstract:Objective To study the biocompatibility of silk fibroin/poly L-lactic acid(SF/PLLA) non-woven network,a kind of new composite tissue engineering nanomaterials,and to explore its possibility as the biological implant materials.Methods  The PLLA non-woven network was prepared by electrostatic spinning.Physiological saline as control,the leaching solution was prepared and injected into the mice,then the mice were observed for 2 weeks.The materials were implanted into the back of the mice,and 3-0 suture was used as control.Tissues were collected at 1,2,3,and 4 weeks after operation,dyed by HE staining and then the  photos were taken.The tissue reactions in experimental group and control group were observed.The rabbit knee joint cartilage cells were cultured,and then subculture cells were seeded to the surface of materials.After cultured in vitro,the adhesion and growth of the cells were observed with  inverted optical microscope.The bioactivities of the rabbit knee joint cartilage cells in negative control group(DMEM culture media),experimental group(DMEM containing materials) and positive control group(DMEM containing phenol solution) were determined by MTT assay after cocultured for 24 and 48 h.Results After injection，the body status of the mice in experimental group was the same to the control group.There were little fibroblasts was  and a little of lymphocytes and macrophage cells in the materials which were implanted into the back of the mice at the beginning.Then the number of the fibroblasts was increased,but the number of the lymphocytes  and macrophage cells did not change obviously.The materials degraded slowly,and the material degraded  obviously at 4 weeks.The inflammation of tissue around the material reduced  gradually from the  2nd week.The inflammation of tissue around the material was the same to the suture,and sometimes was slighter than the suture.After sed for  24 h,there were cells attaching to the fibers of the material.More and more cells attached to the fibers.The reasult of MTT assay showed that the cytotoxicities in experimental groups were all on Level Ⅰ at 24 and 48 h.Except for positive control group,the A values were increased in other groups with the extended response time.At the same time,there was no significant difference in cytotoxicity between experimental group and negative control group(P>0.05) and the A value in experimental group was higher than that in positive control group(P<0.01).Conclusion The SF/PLLA non-woven network scaffold material has good biological compatibility and safety,it could be used as implant material in tissue engineering.

Key words: silk fibroin, poly L-lactic acid, tissue engineering;cartilage, knee joint, biocompatibility, in vitro cytotoxicity, acute general toxicity, short-term local reactions